You forgot that Dylan is now part of the Ranch event. The original story was only about Sophia/Patricia at the ranch, so a revision of the story draft is going to happen. It will add some new paths, which could be Sophia/Dylan, Dylan/Patricia, or Sophia/Dylan/Patricia. Also, Sophia mentioned a girl who's around Dylan's age, so is he going to introduce another character into the story?
If I had to guess, it would likely be around 2.5 to 3 years because he has to create the new environment as well. But then again, it seems he is moving toward AI, which means the characters look much different now, so that could speed up the process, but it is doubtful.